1. Field of the Invention
The present invention relates to a toner for toner-jetting used in a toner-jet system, wherein the toner from a toner-supporting member is jettingly adhered to a recording medium, such as a paper and the like in a direct manner to form an image while said toner-supporting member and recording medium are maintained in a noncontact state.
2. Description of the Related Art
As an apparatus for copying (printing) images, such as characters, figures and the like, an electrophotographic apparatus has generally been used heretofore. However, there are problems that a size of said apparatus grows larger and a manufacturing cost of said apparatus increases because in said apparatus, a latent image is formed on a surface of an image-supporting member (a photosensitive member), and a formation (development) of the image is carried out by adhering a toner to the latent image formed on the supporting member in order to make the latent image visible, and then the toner image obtained on the supporting member is transferred to the recording medium.
Therefore, a toner-jetting system (a direct recording method) has been proposed, in which a recording medium, such as a paper and the like is conveyed between a recording electrode and a back electrode that are arranged on the opposite side of a toner-supporting member, and a toner is electrostatically charged by impressing a voltage corresponding to an image signal between the recording electrode and the back electrode, and then the toner from the toner-supporting member is jettingly adhered to the recording medium in a direct manner according to a state of the impressed voltage.
However, in such a toner-jetting system wherein the toner passes through many holes of the recording electrode at the time of flight of the toner from the toner-supporting member to the recording member, the problem has been arisen that the toner adheres to the recording electrode to clog up the many holes of the recording electrode when the toner makes a flight from the toner-supporting member to the recording member.
Besides, such a recording method brings about a problem that an image noise occurs when an electrification amount of the toner is changed by a change of circumstance as well as a change of the toner with the passage of time. For example, said recording method poses the problems that a phenomenon wherein dots are stretched and distorted toward a moving direction of the paper (a trailing or tailing) takes place in case of printing dots, and that a phenomenon wherein the toner particles are scattered between the lines on a texture region of the paper caused by an impact force at the time of impacting the toner particles on the paper as well as a repulsion force between the toner particles (a scattering) occurs in case of printing lines. Moreover, there are a problems that an image density decreases as it is difficult to smoothly adhere the toner on the recording medium and that even if the toner could be adhered on the recording medium, a sharpness of the image decreases as a boundary between the toner region and the texture region of the paper gets broad (obscure) and the boundary cannot clearly be recognized.
Additionally, there is a problem that the above-mentioned problems become more seriously when an electrification amount of the toner is relatively high because the apparatus using the toner-jetting system mentioned above shows a marked tendency that an optimum electrification amount of the toner is changed depending on a setting condition of the apparatus.